In the profession of drag racing, drivers strive to cover a fixed distance in a preselected time and the difference between winning and losing a race is often measured in thousandths of a second. Accordingly, the nature of a drag race places importance on the consistency of operation of the mechanisms of the car and the consistency of the reaction time of the driver with the result that getting off to a near perfect start being a matter of extreme importance to race car drivers.
In one form of drag racing, cars may cross the starting line only after the green light or starting light comes on. If the car crosses the starting line prior to the green light, the driver is said to have “red lighted” and automatically loses. Conventional drag race cars are equipped with a transmission brake which comprises a solenoid which when energized holds the car at the starting line thereby allowing the driver to apply high RMP of the engine of the car prior to the start of the race and to maintain the engine at or near maximum power until the solenoid is de-energized.
Typically, the start of a drag race is first initiated by a series of yellow lights which are illuminated in sequence with each light being illuminated for five-tenths of a second before the green light appears. Thus, the driver of a drag race car is in a position to judge the time the green light will illuminate and react by releasing an electro-mechanical starting switch which the driver has been holding down by use of continuous hand pressure to electronically disengage the transmission brake. Upon disengagement of the transmission brake, the car will accelerate down the track.
In order to achieve an ideal start reaction time, taking into account all of the variables involved, such as:                1) The rollout distance which can differ from:                    a) racetrack to racetrack;            b) left lane to right lane;            c) day to day due to race organization checking and resetting/adjusting/calibrating the rollout distance.                        2) Brightness of the light bulbs which translates to response time of the driver to react to the first sight of the bulb coming on, which can differ by:                    a) type of bulbs used ie: incandescent vs. LED bulbs;            b) intensity of the bulbs which is adjustable by the timing control system;            c) the outside lighting conditions varying from bright and sunny to nighttime darkness. As well as direct sunlight shining on the bulbs depending on racetrack North, East, South or West orientation and time of day;                        3) The actual response time and accuracy repeatability of the sensors of the timing system which can differ due to:                    a) brand name of sensors; and            b) manufacturing quality control of the brand.                        
The requirement for an adjustable switch (that is within the legal description of the rules) that allows the driver to adjust the delay time ranging from extremely rapid release time to maximum delay time that can be accomplished following the guidelines of the rule limitation maximum of 3-inch length is necessary due to all the variables listed above and allows the driver to place himself in the position to attain an ideal start reaction time.
Unfortunately the setting of the amount of delay of a conventional switch has to be completed prior to entering the staging positions as the driver does not have the time available to make a mechanical adjustment. In race conditions, situations can occur when the driver has a need for an instantaneous choice for a 2nd stage of additional delay available on demand. These situations occur in the event of:                a) accidentally staging too deep, and hence there is less time or rollout available;        b) last minute lane to lane switching forcing the driver to race in a lane that may have a shorter rollout;        c) dusk to nighttime darkness advancing quicker than anticipated making it necessary for more delay.all of which would result in a red light start and an instant loss.        
It is therefore desirable to provide dual 2 stage differential release delayed timing, available instantaneously on demand, but not limited to 2 stages, in addition to delay adjustability in the more conventional method of a moveable travel stop.